Intestines in the Time of Cholera

The world has experienced 7 cholera pandemics since 1817. The first six were caused by the classic biotype of the O1 serogroup of Vibrio cholerae. The 7th pandemic which began in 1961 and is still ongoing (with spread to Haiti and Mexico) is due to the less virulent El Tor biotype of O1 V.cholerae.  In a project, my colleagues and I estimated global cholera costs as exceeding $3 billion annually. 

It was in 1849 during the 2nd pandemic that Dr. John Snow made his pathbreaking epidemiological discovery regarding the role of water in the spread of the cholera microbe--yet to be identified (see The Ghost Map and The Strange Case of the Broad Street Pump). During that pandemic, Dr. John Neill of Philadelphia preserved an intestine from a patient for further study.

The New England Journal of Medicine just published the results of a successful attempt to extract the cholera microbe from that over-a-century old specimen. 

The bacterium recovered was of the classical biotype (as predicted) and had a striking similarity to the reference strain of the classic biotype suggesting that little evolution has occurred since 1849 because of some selective pressure that is constraining its genome. 

Cholera is a fascinating disease--see its biography--and this study fills in a few chapters in its life with humans.

Bird Flu: Flying North to Canada

The Canadian Press is reporting an imported case of H5N1 avian influenza--which was fatal-- in the province of Alberta. From press reports, it appears the infected person traveled to Canada from China. Contact tracing is ongoing, however the highly fatal H5N1 (unlike seasonal influenza) does not efficiently spread between people.

The press report also states that the hospital did "everything it could." In the coming days it will be interesting to find out the clinical course of this patient and what interventions were attempted (e.g. prone ventilation, ECMO, peramivir, zanamivir, etc.) 

Though this is the 1st case of H5N1 identified in North America, it is not surprising that such a case has finally occurred given the density of travel. 

Dallas Buyers Club: Bureaucracy vs. Life

Today I saw the movie Dallas Buyers Club and I thoroughly enjoyed it. The movie is focused on the early days of the AIDS pandemic in America and the struggle to find effective treatments.

Circa 1985, there was little a physician could do to forestall the inevitable death sentence imposed by the diagnosis of HIV infection. The movie portrays the real life efforts of Ron Woodruff to bring novel anti-HIV medications to the US, despite staunch opposition from the FDA.

Woodruff, expertly played by Matthew McConaughey (nominated for awards for this role), displays heroic intransigence in the face of a diagnosis of AIDS and the opposition of the FDA to his work. Throughout the film, it is the FDA that poses a greater threat to his life than the deadly virus because of their insistence that the drugs he employs, some of which were later FDA approved (e.g. ddC) were not safe and merited confiscation and destruction. Another drug Woodruff imported, Peptide T, may yet also find a place in the treatment of HIV.

Today, efficectiveHIV drugs are plentiful. This situation is due, in part, to the efforts of AIDS activists who would not allow bureaucracy to stifle their will to live. However, not all diseases share this status and many conditions could benefit from the efforts of a Woodruff-like character.

The tagline for the movie--"Dare to Live"--is a perfect encapsulation of Woodruff's heroism. We should all follow his example.

Snap, Crackle, Pop: You have Malaria

 Malaria, historically one of mankind's perpetual scourges, continues to devastate populations of humans worldwide. While effective treatments are available, the condition must be diagnosed first--a challenge in resource poor areas.

The diagnosis of malaria is based upon the  visual identification of parasites in a blood sample. Rapid antigen detection tests and PCR can also be used on blood samples.

A novel method, devoid of the need for blood samples, has just been described in a paper published in PNAS. The New York Times reported on the finding. 

The test is based upon detecting the acoustic signature of hemozoin molecules which are degradation products generated by the malaria parasites feasting on the red blood cell's hemoglobin. Using a laser device, hemozoin molecules can be vaporized and the acoustic signature of that process detected allowing malaria to be diagnosed.

Such a test, if technically feasible and scalable, has the potential to transform the way malaria is diagnosed enhancing accuracy and speed while diminishing the need for laboratory and phlebotomy equipment--potentially a giant leap forward.

Influenza: City flu vs. Country flu?

A recent news article reveled that my hometown, Butler County (PA), has the 3rd highest number of reported flu cases in the state with 121 reported cases.

I find that surprising given that our population is no where near the top of the list of the 67 counties that comprise Pennsylvania.

I don't think Butler County can have more influenza cases than Philadelphia County.

A couple of factors may be responsible for this disproportionate ranking:

• Many hospitals, given flu activity is widespread, may be making clinical diagnoses of influenza rather than running diagnostic tests
• The rapid influenza antigen test, which is used in many smaller hospitals (including in Butler), detects about a half of flu cases

In general, influenza diagnostics are very limited because of the unreliability of rapid antigen tests coupled with the fact that influenza PCR is done at few institutions and, when available, has a long turn-around-time.

However, I do recommend people avail themselves of whatever influenza diagnostics they have available in order to have some estimate available of influenza spread, alert infection control regarding hospitalized influenza patients, and to emphasize the need for antiviral treatment--which should not be withheld based on a negative rapid antigen test.